DETERMINATION OF PINDOLOL ENANTIOMERS IN HUMAN PLASMA AND URINE BY SIMPLE LIQUID-LIQUID-EXTRACTION AND HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A simple method for the measurement of pindolol enantiomers by HPLC is presented. Alkalinized serum or urine is extracted with ethyl acetate and the residue remaining after evaporation of the organic layer is t hen derivatised with (S)-(-)-alpha-methylbenzyl isocyanate. The diaste reoisomers of derivatised pindolol and metoprolol (internal standard) are separated by high-performance liquid chromatography (HPLC) using a C-18 silica column and detected using fluorescence (excitation lambda : 215 nm, emission lambda: 320 nm). The assay displays reproducible li nearity for pindolol enantiomers with a correlation coefficient of r(2 ) greater than or equal to 0.998 over the concentration range 8-100 ng ml(-1) for plasma and 0.1-2.5 mu g ml(-1) for urine. The coefficient of variation for accuracy and precision of the quality control samples for both plasma and urine are consistently <10%. Assay parameters are similar to those of previously published assays for pindolol enantiom ers, however this assay is significantly easier and cheaper to run. Cl inically relevant concentrations of each pindolol enantiomer can readi ly be measured. (C) 1998 Elsevier Science B.V. All rights reserved.